Prescott-256 Celeron D processors, initially launched 25 June 2004, featuring double the L1 cache (16 KB) and L2 cache (256 KB) as compared to the previous Willamette and Northwood desktop Celerons, by virtue of being based on the Prescott Pentium 4 core.It also features a 533 MT/s bus and SSE3, and a 3xx model number (compared to 5xx for Pentium 4s and 7xx for Pentium Ms). The Prescott-256 Celeron D was manufactured for Socket 478 and LGA 775, with 3x0 and 3x5 designations from 310 through to 355 at clock speeds of 2.13 GHz to 3.33 GHz.